Hundreds of thousands of operations are performed annually on benignly enlarged prostates. A significant percentage of all patients do not improve after the operation while others develop new difficulties such as incontinence and impotence. There is also a mortality rate associated with the operation.
Traditionally, the field of urology has not focused attention on differential diagnosis of "outflow obstruction" and "bladder failure" in order to assess candidates prostatectomy (which as used herein includes transurethral prostatic resection or "TURP"). It is one of the merits of this invention that such parameters, which have recently proven to be of value in the differential diagnosis, can now routinely be included in the assessment for prostatectomy.
Urodynamic measurement systems of the prior art traditionally include appropriate transducers for generating pressure and flow rate signals during voiding, i.e., micturition. From these signals, it is possible to generate and display a pressure/flow rate curve, i.e., a representation plotting the pressure in the bladder against the urinary flow rate during micturition. Some experienced urologists are able to analyze this data and differentiate between "seriously obstructed patients" and "certainly non-obstructed patients." Such assessment, however, is based on visual subjective inspection of the shape of the plot, without any quantitative specification. The treatment decision is thus based on this subjective impression of the treating urologist and other clinical observations and tests including rectal palpation, residual urine assessed by ultrasound of the bladder, ultrasound of the prostate, free uroflowmetry and optional cystoscopy. None of these examinations, however, supply an objective, quantitative measure to determine either the degree of obstruction or the degree of bladder failure.
Thus, in the prior art even experienced urologists cannot objectively assess the indication for therapeutic interventions or evaluate their effect. This is also true for gynecologists who at present have no objective means to make a differential diagnosis between women with voiding complaints due to "urinary outflow obstruction" and/or impaired detrusor contractility.